1. Field of the Invention
The present invention relates to an input pen, and more particularly, to an improved input pen which is manually operated to move on an operation surface of a capacitance-detecting coordinate input device, and provides high operability for any operator.
2. Description of the Related Art
In a conventional type of compact capacitance-detecting coordinate input device (referred to as a "tablet" hereinafter), an operation surface thereof was initially operated with the finger of the operator.
However, since the contact area of the fingertip for touching the operation surface of the tablet cannot be reduced below a fixed area, it is impossible to precisely set a coordinate position on the operation surface, and to input the coordinate position with high accuracy.
In order to eliminate such a disadvantage, the operation surface of tablets has been recently operated with an input pen (stylus pen) instead of the finger. The input pen (stylus pen) is formed, for example, by fitting a metal operating member into one end of a rod-like metal body, and cutting the tip of the metal operating member obliquely with respect to the axial direction thereof so as to form an operating section.
FIG. 4 is an outward view showing a structure of the aforesaid well-known input pen (stylus pen).
As shown in FIG. 4, an input pen (stylus pen) 40 is formed by fitting the base of a hollow cylindrical metal operating member 42, which is provided with an operating section 42S formed by cutting the tip obliquely with respect to the axial direction, into one end of a rod-like hollow metal body 41.
In operating an operation surface of a tablet (not shown) with this input pen (stylus pen) 40, the operator grips the metal body 41 as if to hold a pencil or a writing pen, brings the operating section 42S of the metal operating member 42 into contact with the operation surface of the tablet while keeping at least one finger in contact with the metal operating member 42, and appropriately moves the contacting operating section 42S on the operation surface of the tablet, thereby inputting the coordinate position.
The operating section 42S of the metal operating member 42 in the above known input pen (stylus pen) 40 forms a predetermined angle a with the operation surface of the tablet. However, even if the angle .alpha. is convenient for some operators in inputting the coordinate position through the input pen 40, it is not always convenient for others, and therefore, the input pen 40 does not have good operability for all operators.
Furthermore, the above input pen (stylus pen) 40 is required to be temporarily separated from the operation surface of the tablet on tapping entry that alternates electrical connection and disconnection with the operating surface, which also lowers its operability.